A study on controlling chloroform in drinking water using Chlorine Dioxide as first disinfector followed by chlorine as secondary disinfector was reported. Using chlorine dioxide as pretreatment disinfector would decrease the concentration of chloroform in drinking water. Chlorination after chlorine dioxide pretreatment may be influenced by reaction time and temperature. Additionally, when the mixture which composed of chlorine and chlorine dioxide was used, with the content of chlorine dioxide in mixture disinfector increasing, chloroform in the sample treated by it may decrease obviously.